Intake gaskets leaking burning coolant?
 

I recently (as in yesterday) bought a 97 f250 with 145k. the truck is in pretty good shape and runs great. tonight i was driving home and noticed the white smoke from the tailpipe. not good. so as best as i can tell it loads up on coolant when the engine is in a high vacuum scenario. deceleration and idle. if you are accelerating the smoke clears up and goes away. the coolant that hasnt been burned away is nasty looking and smells strongly of gas. there is no sign of water in the oil as of yet. it also didnt seem like the cooling system was over pressurized. does this seem more like a head gasket or could it be the intake? my knowledge of these engines is lacking in comparison to my GM knowledge. i have owned one before but it was always great and never thought of giving me issues. any help is greatly appreciated

Ryan

is your oilfilter mounted on a oil/coolant heat exchanger that has antifreeze running thru it? might be an internal leak inside the cooler,or headgasket

i dont think its the heat exchanger. it is burning the coolant and the coolant has gas in it, not oil. the oil was quite nasty.

i have got the upper plenum removed and all of the harness and vacuum out of the way. the plenum has the coolant/gas gunk in it. is there a reasonable way that the coolant would get up into the dry plenum from a head gasket failure? it seems that it would have to be an intake gasket failure for that to happen. the only way the intake would get coolant in it from the head gasket would be the intake valve and if that is open the cylinder is in a vacuum. so it would suck the coolant into the cylinder but as cylinder pressure builds the intake has to be closed, effectively sealing the passage to the intake plenum. does this make sense?

So, new head gaskets and new intake etc. still blowing steam when i finally got it fired up about 15 minutes ago. i am about to go drive it off the side of a mountain. i am not sure about the heat exchanger thingamajig. would that cause it to blow steam? i dont even know if it has one. the lower rad hose doesnt tie directly into the WP but goes some box that seems as though its associated with the oil filer mount.

so any ideas as to why it would still be clouding the neighborhood and filling the pan with water?

Ryan

Earlier in the thread you stated there was no water in the oil but now you say it's filling the pan with water. Do you mean the oil pan?

Did your oil level go up?

The box on the lower radiator hose is the infamous water to oil heat exchanger fitted from mid 89 through 1997 460 EFI engines. The steam and gunk is from two way leaks, oil into radiator when running, then radiator into oil when you shut it off hot. Look at this thread: https://www.ford-trucks.com/forums/9...r-failure.html

i may have been a little hasty in saying that. in the first failure a couple of weeks ago the oil was defiantly contaminated. when i made that post i thought it wasnt, but i was wrong. after replacing the head gaskets and intake gaskets it is still burning water. i have let it sit for the last few hours and the oil level isn't up. the water that is visible in the radiator appears clean and not oily. i at first thought it had gained some volume in the oil pan but i yanked the dipstick right after it had been running and it was just splash i believe. after sitting it is down where it should be. actually its a quart low, but i underfilled it so that isnt odd. what is on the stick looks like nice clear new oil. i will pop the drain plug and see if any water oozes out first tomorrow

it didnt really run long enough to open the thermostat but if the two were mixing in the oil cooler/heat exchanger i am sure it would show in the radiator as there is no block between the lower rad hose and the oil cooler box thingy.
as it is the water doesnt appear extremely contaminated. it does have a slight murk to it, but the residue from the first problem would also explain that. no obvious oil on top.

tomorrow i am going to pull the plugs and see if i get water from any cylinders. last time it was the back two. if there isnt any water in the cylinders i think i can guess that the intake system is possibly the culprit. i may also try pressurizing the cooling system and seeing if i can hear anything that could give me a hint. maybe ill get lucky and the leak will be obvious and squirt me in the eye or something...

Ryan

it doesnt seem as if that is the problem(although i may address it before it becomes one). the radiator has no oil in it now and after the original issue it didn't have oil in it that i could see. it did smell really gassy and have a nasty color. it was clearish and a funky color that slowly returned to more normal green as the bucket sat in my garage.

in the original condition the oil was contaminated. i think the intake gasket was to blame for that.

i read through that post today after i made my post here. good info, just not what i am fighting now i dont think

ryan

you could have the cooling system pressurized with air from a comrpessor about 15lbs or so. i have made my own homemade fittings in the past and hooked it to a small air compressor, they sell airpump tools for this ,with complete silence you can hear the air leaking into the engine,i got rid of that oilcooler yeah its that stupid box looking thing your waterpump hose hooks to. not a good design too risky to have it in my opinion